Development of beam extraction chamber for 750 keV DC accelerator

The 750 keV DC Industrial Accelerator has about five metre long beam line. High vacuum is maintained in this beam line and electron beam travels inside this line. The material to be irradiated is conveyed outside the beam line. Beam extraction system acts as a barrier between high vacuum region and atmosphere. Electron beam, which is generated and accelerated in high vacuum region passes through this system and enters the atmosphere region where it will penetrate into the material being processed. Also this system helps in distributing the beam loss heat load over a large area on the extraction window foil to minimize the chances of window foil rupture due to overheating. In the process of accomplishing these objectives, the beam loss and its divergence are to be kept minimum. Beam extraction system consists of scanning magnet assembly, scanning coil power supply, extraction chamber, extraction window consisting of flanges, foil and vacuum seals, water cooling and air cooling systems, support structure